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CO/苯乙烯光学活性交替共聚物的合成
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作者 袁建超 吕士杰 《自然科学进展(国家重点实验室通讯)》 2000年第10期941-944,共4页
使用非螯合型手性二膦配体DDPPI(DDPPI:1,4:3,6-dianhydro-2,5-dideoxy-2,5-bis(diphenylphosphino)-L-iditol),在PdCl_2-CuCl_2-DDPPI催化体系中,合成了高全同结构的光学活性CO/苯乙烯交替共聚物。聚合条件是:甲基乙基酮为溶剂,CO压力6... 使用非螯合型手性二膦配体DDPPI(DDPPI:1,4:3,6-dianhydro-2,5-dideoxy-2,5-bis(diphenylphosphino)-L-iditol),在PdCl_2-CuCl_2-DDPPI催化体系中,合成了高全同结构的光学活性CO/苯乙烯交替共聚物。聚合条件是:甲基乙基酮为溶剂,CO压力6.0MPa,70℃下反应72 h。 展开更多
关键词 光学活性共聚物 同结构 间同结构 苯乙烯
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Eco-spatial Structure of Urban Agglomeration 被引量:6
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作者 GUO Rongchao MIAO Changhong +1 位作者 LI Xuexin CHEN Deguang 《Chinese Geographical Science》 SCIE CSCD 2007年第1期28-33,共6页
In terms of ecological theory, this paper makes a comprehensive analysis of the mutualism and co- evolutionary mechanism between the eco-spatial structure and socio-economic development of the urban agglomeration, and... In terms of ecological theory, this paper makes a comprehensive analysis of the mutualism and co- evolutionary mechanism between the eco-spatial structure and socio-economic development of the urban agglomeration, and maps out optimized modes of the eco-spatial structure of the urban agglomeration. The analysis is a case study of the urban agglomeration on different levels of global, national, provincial and local scales, on the basis of those conclusions are drawn: 1) Within the scope of the urban agglomeration, the cities should be reasonably sized and appropriately densified; the spatial combination of the urban agglomeration ought to be orderly, and its eco-spatial structure ought to be optimized and efficient; the relationship between the economic society and eco-spatial environment ought to be that of mutual benefit and co-evolution. 2) “The mode of corridor group network” is a certain trend evoked from the spatial structure of urban agglomeration. 3) The eco-spatial structure of urban agglomeration under “the mode of corridor group network” can further increase the environmental capacity of urban agglomeration, and is in favor of the harmonious relationship between man and nature. 展开更多
关键词 mutualism theory co-evolution theory urban agglomeration eco-spatial structure corridor group network
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Quotient space model based on algebraic structure 被引量:3
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作者 陈林书 WangJiayang +1 位作者 LiLi YangZhenghua 《High Technology Letters》 EI CAS 2016年第2期160-169,共10页
In the quotient space theory of granular computing,the universe structure is assumed to be a topology,therefore,its application is still limited.In this study,based on the quotient space model,the universe structure i... In the quotient space theory of granular computing,the universe structure is assumed to be a topology,therefore,its application is still limited.In this study,based on the quotient space model,the universe structure is assumed as an algebra instead of a topology.As to obtain the algebraic quotient operator,the granulation must be uniquely determined by a congruence relation,and all the congruence relations form a complete semi-order lattice,which is the theoretical basis of granularities ' completeness.When the given equivalence relation is not a congruence relation,it defines the concepts of upper quotient and lower quotient,and discusses some of their properties which demonstrate that falsity preserving principle and truth preserving principle are still valid.Finally,it presents the algorithms and example of upper quotient and lower quotient.The work extends the quotient space theory from structure,and provides theoretical basis for the combination of the quotient space theory and the algebra theory. 展开更多
关键词 granular computing quotient space congruence closure quotient operation up-per lower quotient
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Exotic Structures of Odd-A Carbon Isotopes in the Deformed Relativistic Mean-FieldTheory
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作者 JIANGWei-Zhou RENZhong-Zhou +2 位作者 ZHUZhi-Yuan WANGTing-Tai HEZe-Jun 《Communications in Theoretical Physics》 SCIE CAS CSCD 2004年第1期79-88,共10页
We study contributions of the pion meson and spatial component of the omega meson in the odd-A carbon isotopes. The pion and spatial omega provide small attractions in odd-A nuclei, giving rise to considerable influen... We study contributions of the pion meson and spatial component of the omega meson in the odd-A carbon isotopes. The pion and spatial omega provide small attractions in odd-A nuclei, giving rise to considerable influences on the single-particle energies rather than the bulk properties such as total binding energies, and root-mean-square (rms) radii. The ±? (spin) splittings, arising from the spatial omega, are large in <SUP>11</SUP>C and <SUP>13</SUP>C and drop as the isospin rises in odd-A carbon isotopes. As an isovector, the pion can shift slightly the relative potential depth of neutron and proton, contrary to the role of the rho meson. There is a general trend that both the pion and spatial omega fields reduce with the rise of isospin in the isotopic chain. From the normal nucleus to halo nucleus, an abnormal drop of the pion or spatial omega field may occur, as can be seen in <SUP>19</SUP>C, <SUP>15</SUP>C, and <SUP>21</SUP>C. 展开更多
关键词 halo nuclei relativistic mean-field theory
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聚(1,4-环己二烯碳酸酯)立体低聚物的合成及微结构分析 被引量:2
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作者 王霞弟 孙星宇 +3 位作者 罗婧 朱晴 周辉 吕小兵 《高分子学报》 SCIE CAS CSCD 北大核心 2021年第10期1316-1322,共7页
聚合物微结构控制是配位催化聚合领域最重要的目标之一.而合成各种立构规整性低聚物及其核磁碳谱研究是聚合物微结构定性和定量分析的关键.本文以手性环己-4-烯-1,2-二醇为原料,采用N,N'-羰基二咪唑和三光气作为羰化试剂,设计合成了... 聚合物微结构控制是配位催化聚合领域最重要的目标之一.而合成各种立构规整性低聚物及其核磁碳谱研究是聚合物微结构定性和定量分析的关键.本文以手性环己-4-烯-1,2-二醇为原料,采用N,N'-羰基二咪唑和三光气作为羰化试剂,设计合成了CO_(2)/1,2-环氧-4-环己烯交替共聚物(聚(1,4-环己二烯碳酸酯),PCEC)全同立构和间同立构的二聚体、四聚体、六聚体、八聚体和十二聚体模型化合物.通过分析全同立构和间同立构模型化合物的核磁碳谱,完成了PCEC微结构的碳谱信息归属.发现聚合物全同立构序列的羰基、次甲基和亚甲基区域的出峰位置分别在δ=154.04、73.83和29.91;间同立构序列的羰基、次甲基和亚甲基区域的出峰位置分别在δ=153.72、72.97和28.98. 展开更多
关键词 二氧化碳 聚碳酸酯 同结构 间同结构 核磁碳谱
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Bimodule and twisted representation of vertex operator algebras
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作者 JIANG QiFen JIAO XiangYu 《Science China Mathematics》 SCIE CSCD 2016年第2期397-410,共14页
In this paper, for a vertex operator algebra V with an automorphism g of order T, an admissible V-module M and a fixed nonnegative rational number n ∈1/T Z_+, we construct an A_(g,n)(V)-bimodule Ag,n(M) and study its... In this paper, for a vertex operator algebra V with an automorphism g of order T, an admissible V-module M and a fixed nonnegative rational number n ∈1/T Z_+, we construct an A_(g,n)(V)-bimodule Ag,n(M) and study its properties, discuss the connections between bimodule A_(g,n)(M) and intertwining operators. Especially, bimodule A _(g,n)-1T(M) is a natural quotient of A_(g,n)(M) and there is a linear isomorphism between the space IM^k M Mjof intertwining operators and the space of homomorphisms HomA_(g,n)(V)(A_(g,n)(M) A_(g,n)(V)M^j(s), M^k(t)) for s, t ≤ n, M^j, M^k are g-twisted V modules, if V is g-rational. 展开更多
关键词 BIMODULE g-twisted module vertex operator algebra intertwining operator fusion rules
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Unveiling the charge density wave inhomogeneity and pseudogap state in 1T-TiSe_2
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作者 Kai-Wen Zhang Chao-Long Yang +8 位作者 Bin Lei Pengchao Lu Xiang-Bing Li Zhen-Yu Jia Ye-Heng Song Jian Sun Xianhui Chen Jian-Xin Li Shao-Chun Li 《Science Bulletin》 SCIE EI CSCD 2018年第7期426-432,共7页
By using scanning tunneling microscopy(STM)/spectroscopy(STS), we systematically characterize the electronic structure of lightly doped 1 T-TiSe_2, and demonstrate the existence of the electronic inhomogeneity and the... By using scanning tunneling microscopy(STM)/spectroscopy(STS), we systematically characterize the electronic structure of lightly doped 1 T-TiSe_2, and demonstrate the existence of the electronic inhomogeneity and the pseudogap state. It is found that the intercalation induced lattice distortion impacts the local band structure and reduce the size of the charge density wave(CDW) gap with the persisted 2 × 2 spatial modulation. On the other hand, the delocalized doping electrons promote the formation of pseudogap. Domination by either of the two effects results in the separation of two characteristic regions in real space, exhibiting rather different electronic structures. Further doping electrons to the surface confirms that the pseudogap may be the precursor for the superconducting gap. This study suggests that the competition of local lattice distortion and the delocalized doping effect contribute to the complicated relationship between charge density wave and superconductivity for intercalated 1 T-TiSe_2. 展开更多
关键词 Charge density wave Pseudogap TiSe2 Scanning tunneling microscopy Scanning tunneling spectroscopy
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